1. Field of the Invention
This invention relates to crimp sleeves or crimp rings for crimping around a piece of flexible tubing to secure the tubing to a nipple of a fitting or the like in order to provide a leak-free connection.
2. Description of the Related Art
Flexible tubing, such as PEX (cross-linked polyethylene) tubing is used in radiant heating systems and is being used in place of rigid pipe in residential plumbing systems with increasing frequency. This type of tubing is easier to install than conventional rigid pipe since it can be routed around obstacles without adding elbows and the like to accomplish the bend. When flexible tubing needs to be fastened to a fitting, fixture, valve, or the like, the tubing is pushed onto a nipple of the fitting such that the nipple is received inside of the tubing. A crimp ring is then placed around the tubing in the area over the nipple and crimped in place using a crimping tool to complete the connection.
Crimp rings are typically simple sleeves of brass, copper or the like which are slid over the tubing and crimped in place. A newer device for fastening PEX tubing to a nipple is the Viega PureFlow® Stainless Steel Press Sleeve, which comprises a stainless steel sleeve having a first end which is open for insertion of the tubing and a second end having an inwardly projecting annular flange which provides a stop for the tubing. Use of this product assists in locating the crimp at the correct position relative to the end of the tubing, since the addition of the stop more or less fixes the location of the sleeve on the tubing. A single view hole is provided through the sleeve near the annular flange so that an installer can see whether the tubing is inserted a sufficient distance into the sleeve.
A problem with any of the prior art crimp sleeves is that they must be manually positioned on the tubing before the tubing is pushed onto the nipple. If the installer forgets and installs the tubing on the nipple before placing the sleeve on the tube, the tubing will usually need to be removed from the nipple and the sleeve installed. Nipples used in these applications typically include barbs for retaining the tubing so that pulling the tubing off of the nipple may be difficult and might require cutting of the tubing. There is significant risk of damaging the fitting or fixture. Crimp sleeves are also frequently lost.
What is needed is a crimp sleeve which can be pre-installed or pre-loaded onto the nipple so that it is always in position for attachment of the tubing. The sleeve would preferably be securely attached to the nipple so that it wouldn't be easily dislodged.
Furthermore, a crimp sleeve which could alternatively be securely pre-installed on the end of a length of tubing would also be advantageous. Such a crimp sleeve could be installed on the tubing before the tubing is pressed onto the nipple and would not fall off during the installation process.